An investigation for drunk driving begins when a police officer has “reasonable grounds” to believe that a person has driven a vehicle in the past three hours with alcohol his/her system.  Simply put, if a police officer thinks a person has driven in the last three hours with alcohol in his/her body, the police officer may start investigating.

Obtaining “Reasonable Grounds”

Drunk driving investigations almost always begin with a person inside a vehicle.  Because of this, police do not have a hard time proving reasonable grounds to believe that a person was driving.  Here are some of the ways that police come up with “reasonable grounds” to believe that a person has alcohol in his/her system.

  • A person is showing physical signs such as
    • Slurred speech,
    • Unsteadiness on their feet,
    • Glassy eyes,
    • Poor coordination,
  • The police officer can smell alcohol on the person’s breath,
  • The person told police that s/he has drank alcohol,
  • Evidence of bad driving can also used to come up with “reasonable grounds”.

Breath Demand for Approved Screening Device (ASD)

Once an officer has “reasonable grounds” to believe that a person has alcohol in his/her system, the officer can ask that the person provide a sample of his/her breath into an approved screening device.  An approved screening device is not that same as a breathalyzer.  Approved screening devices analyze a person’s breath to measure the amount of alcohol in every 100mL of a person’s blood.  If a person has less than 80mg, the machine will show a “pass”.  A person who “blows” a pass will not be charged.  If a person “blows” between 50mg and 100mg the machine will show a “warn”.  A person who “blows” a warn faces a driver’s license suspension for a maximum period of thirty days.  If a person “blows” 100mg, it will show a “fail”.  A person that blows over 100mg can be asked by police to give another breath sample into a breathalyzer at a police station.

Refusing a demand for an ASD is a crime.

Breathalyzer Demand

A breathalyzer is a machine that determines the exact amount of alcohol that a person has in his/her blood.  Unlike the screening device, it is more precise.  An officer can make a demand for a person’s breath into a breathalyzer if s/he has “reasonable grounds” to believe that the person has committed a drunk driving offence within the past three hours.  The most common way for a police officer to get grounds is from information that is gained from an approved screening device.  If a person “blows” a fail into an approved screening device immediately after driving, this will give police grounds to make a demand.

In law there is something called the “presumption of identity”.  This means that an analysis of a sample from a breathalyzer can be concluded to be what a person’s blood alcohol content was at the time of driving under the following conditions:

  • A lawful breath demand was made,
  • Each sample was made “as soon as practicable” after the time of the offence,
    • As soon as practicable means that it must be done in a reasonably quick amount of time when taking the circumstances into consideration,
  • Two samples are taken no less than fifteen minutes apart,
  • The first sample is taken within two hours of the offence,
  • Each sample was taken into an approved machine or device,
  • The device was operated by a “qualified technician”,
    • A qualified technician is a person that is properly trained to use a breathalyzer machine that is recognized by the Attorney General,
  • The results of the sample were analyzed by a qualified technician.

If a person “blows” “over 80” (the legal limit of 80mg in every 100mL of blood) s/he can be charged with a drunk driving offence.  If a person is charged with a drunk driving offence, his/her license will be suspended administratively for a period of 90 days.

Refusing a breathalyzer demand is a crime.

Call a Drunk Driving Lawyer

Lakin Afolabi is a impaired driving/dui lawyer in London, Ontario who has won acquittals for people charged with drunk driving on numerous occasions.  If you or a person you know has been charged with a drunk driving offence contact him anytime.